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<h2 class='header'><a href='src--filemanager--file.c.html#L85' title='Included from 85 in src/filemanager/file.c.'>INCLUDED FROM</a></h2>
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<h2 class='header'>DEFINITIONS</h2>
This source file includes following definitions.
<ol>
<li><a href='#L81' title='Defined at 81.'>io_blksize</a></li>
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<pre>
<a id='L1' name='L1'></a>   1 <em class='comment'>/* I/O block size definitions for coreutils</em>
<a id='L2' name='L2'></a>   2 <em class='comment'>   Copyright (C) 1989-2016 Free Software Foundation, Inc.</em>
<a id='L3' name='L3'></a>   3 <em class='comment'></em>
<a id='L4' name='L4'></a>   4 <em class='comment'>   This program is free software: you can redistribute it and/or modify</em>
<a id='L5' name='L5'></a>   5 <em class='comment'>   it under the terms of the GNU General Public License as published by</em>
<a id='L6' name='L6'></a>   6 <em class='comment'>   the Free Software Foundation, either version 3 of the License, or</em>
<a id='L7' name='L7'></a>   7 <em class='comment'>   (at your option) any later version.</em>
<a id='L8' name='L8'></a>   8 <em class='comment'></em>
<a id='L9' name='L9'></a>   9 <em class='comment'>   This program is distributed in the hope that it will be useful,</em>
<a id='L10' name='L10'></a>  10 <em class='comment'>   but WITHOUT ANY WARRANTY; without even the implied warranty of</em>
<a id='L11' name='L11'></a>  11 <em class='comment'>   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the</em>
<a id='L12' name='L12'></a>  12 <em class='comment'>   GNU General Public License for more details.</em>
<a id='L13' name='L13'></a>  13 <em class='comment'></em>
<a id='L14' name='L14'></a>  14 <em class='comment'>   You should have received a copy of the GNU General Public License</em>
<a id='L15' name='L15'></a>  15 <em class='comment'>   along with this program.  If not, see &lt;http://www.gnu.org/licenses/&gt;.  */</em>
<a id='L16' name='L16'></a>  16 
<a id='L17' name='L17'></a>  17 <em class='comment'>/* Include this file _after_ system headers if possible.  */</em>
<a id='L18' name='L18'></a>  18 
<a id='L19' name='L19'></a>  19 <em class='comment'>/* sys/stat.h will already have been included by system.h. */</em>
<a id='L20' name='L20'></a>  20 <em class='sharp'>#include</em> "<a href='lib--stat-size.h.html'>lib/stat-size.h</a>"
<a id='L21' name='L21'></a>  21 
<a id='L22' name='L22'></a>  22 <em class='comment'>/* *INDENT-OFF* */</em>
<a id='L23' name='L23'></a>  23 
<a id='L24' name='L24'></a>  24 <em class='comment'>/* As of May 2014, 128KiB is determined to be the minimium</em>
<a id='L25' name='L25'></a>  25 <em class='comment'>   blksize to best minimize system call overhead.</em>
<a id='L26' name='L26'></a>  26 <em class='comment'>   This can be tested with this script:</em>
<a id='L27' name='L27'></a>  27 <em class='comment'></em>
<a id='L28' name='L28'></a>  28 <em class='comment'>   for i in $(seq 0 10); do</em>
<a id='L29' name='L29'></a>  29 <em class='comment'>     bs=$((1024*2**$i))</em>
<a id='L30' name='L30'></a>  30 <em class='comment'>     printf "%7s=" $bs</em>
<a id='L31' name='L31'></a>  31 <em class='comment'>     timeout --foreground -sINT 2 \</em>
<a id='L32' name='L32'></a>  32 <em class='comment'>       dd bs=$bs if=/dev/zero of=/dev/null 2&gt;&amp;1 \</em>
<a id='L33' name='L33'></a>  33 <em class='comment'>         | sed -n 's/.* \([0-9.]* [GM]B\/s\)/\1/p'</em>
<a id='L34' name='L34'></a>  34 <em class='comment'>   done</em>
<a id='L35' name='L35'></a>  35 <em class='comment'></em>
<a id='L36' name='L36'></a>  36 <em class='comment'>   With the results shown for these systems:</em>
<a id='L37' name='L37'></a>  37 <em class='comment'>   system #1: 1.7GHz pentium-m with 400MHz DDR2 RAM, arch=i686</em>
<a id='L38' name='L38'></a>  38 <em class='comment'>   system #2: 2.1GHz i3-2310M with 1333MHz DDR3 RAM, arch=x86_64</em>
<a id='L39' name='L39'></a>  39 <em class='comment'>   system #3: 3.2GHz i7-970 with 1333MHz DDR3, arch=x86_64</em>
<a id='L40' name='L40'></a>  40 <em class='comment'>   system #4: 2.20GHz Xeon E5-2660 with 1333MHz DDR3, arch=x86_64</em>
<a id='L41' name='L41'></a>  41 <em class='comment'>   system #5: 2.30GHz i7-3615QM with 1600MHz DDR3, arch=x86_64</em>
<a id='L42' name='L42'></a>  42 <em class='comment'>   system #6: 1.30GHz i5-4250U with 1-channel 1600MHz DDR3, arch=x86_64</em>
<a id='L43' name='L43'></a>  43 <em class='comment'>   system #7: 3.55GHz IBM,8231-E2B with 1066MHz DDR3, POWER7 revision 2.1</em>
<a id='L44' name='L44'></a>  44 <em class='comment'></em>
<a id='L45' name='L45'></a>  45 <em class='comment'>                per-system transfer rate (GB/s)</em>
<a id='L46' name='L46'></a>  46 <em class='comment'>   blksize   #1    #2    #3    #4    #5    #6    #7</em>
<a id='L47' name='L47'></a>  47 <em class='comment'>   ------------------------------------------------------------------------</em>
<a id='L48' name='L48'></a>  48 <em class='comment'>      1024  .73   1.7   2.6   .64   1.0   2.5   1.3</em>
<a id='L49' name='L49'></a>  49 <em class='comment'>      2048  1.3   3.0   4.4   1.2   2.0   4.4   2.5</em>
<a id='L50' name='L50'></a>  50 <em class='comment'>      4096  2.4   5.1   6.5   2.3   3.7   7.4   4.8</em>
<a id='L51' name='L51'></a>  51 <em class='comment'>      8192  3.5   7.3   8.5   4.0   6.0  10.4   9.2</em>
<a id='L52' name='L52'></a>  52 <em class='comment'>     16384  3.9   9.4  10.1   6.3   8.3  13.3  16.8</em>
<a id='L53' name='L53'></a>  53 <em class='comment'>     32768  5.2   9.9  11.1   8.1  10.7  13.2  28.0</em>
<a id='L54' name='L54'></a>  54 <em class='comment'>     65536  5.3  11.2  12.0  10.6  12.8  16.1  41.4</em>
<a id='L55' name='L55'></a>  55 <em class='comment'>    131072  5.5  11.8  12.3  12.1  14.0  16.7  54.8</em>
<a id='L56' name='L56'></a>  56 <em class='comment'>    262144  5.7  11.6  12.5  12.3  14.7  16.4  40.0</em>
<a id='L57' name='L57'></a>  57 <em class='comment'>    524288  5.7  11.4  12.5  12.1  14.7  15.5  34.5</em>
<a id='L58' name='L58'></a>  58 <em class='comment'>   1048576  5.8  11.4  12.6  12.2  14.9  15.7  36.5</em>
<a id='L59' name='L59'></a>  59 <em class='comment'></em>
<a id='L60' name='L60'></a>  60 <em class='comment'></em>
<a id='L61' name='L61'></a>  61 <em class='comment'>   Note that this is to minimize system call overhead.</em>
<a id='L62' name='L62'></a>  62 <em class='comment'>   Other values may be appropriate to minimize file system</em>
<a id='L63' name='L63'></a>  63 <em class='comment'>   or disk overhead.  For example on my current GNU/Linux system</em>
<a id='L64' name='L64'></a>  64 <em class='comment'>   the readahead setting is 128KiB which was read using:</em>
<a id='L65' name='L65'></a>  65 <em class='comment'></em>
<a id='L66' name='L66'></a>  66 <em class='comment'>   file="."</em>
<a id='L67' name='L67'></a>  67 <em class='comment'>   device=$(df --output=source --local "$file" | tail -n1)</em>
<a id='L68' name='L68'></a>  68 <em class='comment'>   echo $(( $(blockdev --getra $device) * 512 ))</em>
<a id='L69' name='L69'></a>  69 <em class='comment'></em>
<a id='L70' name='L70'></a>  70 <em class='comment'>   However there isn't a portable way to get the above.</em>
<a id='L71' name='L71'></a>  71 <em class='comment'>   In the future we could use the above method if available</em>
<a id='L72' name='L72'></a>  72 <em class='comment'>   and default to io_blksize() if not.</em>
<a id='L73' name='L73'></a>  73 <em class='comment'> */</em>
<a id='L74' name='L74'></a>  74 
<a id='L75' name='L75'></a>  75 
<a id='L76' name='L76'></a>  76 <strong class='reserved'>enum</strong> <em class='brace'>{</em> <a href='../S/src--filemanager--ioblksize.h.html#L85' title='Referred from 85 in src/filemanager/ioblksize.h.'>IO_BUFSIZE</a> = 128 * 1024 <em class='brace'>}</em>;
<a id='L77' name='L77'></a>  77 
<a id='L78' name='L78'></a>  78 <em class='comment'>/* *INDENT-ON* */</em>
<a id='L79' name='L79'></a>  79 
<a id='L80' name='L80'></a>  80 <strong class='reserved'>static</strong> <strong class='reserved'>inline</strong> <a href='../Y/size_t.html' title='Multiple used in 726 places.'>size_t</a>
<a id='L81' name='L81'></a>  81 <a href='../S/src--filemanager--file.c.html#L2531' title='Referred from 2531 in src/filemanager/file.c.'>io_blksize</a> (<strong class='reserved'>struct</strong> <a href='../Y/stat.html' title='Multiple used in 258 places.'>stat</a> <a href='../Y/sb.html' title='Multiple used in 19 places.'>sb</a>)
     <em class='comment'>/* <img class='icon' src='../icons/n_left.png' alt='[previous]' /><img class='icon' src='../icons/n_right.png' alt='[next]' /><img class='icon' src='../icons/n_first.png' alt='[first]' /><img class='icon' src='../icons/n_last.png' alt='[last]' /><a href='#TOP'><img class='icon' src='../icons/top.png' alt='[top]' /></a><a href='#BOTTOM'><img class='icon' src='../icons/bottom.png' alt='[bottom]' /></a><a href='../mains.html'><img class='icon' src='../icons/index.png' alt='[index]' /></a><a href='../help.html'><img class='icon' src='../icons/help.png' alt='[help]' /></a>&nbsp;<input type='text' readonly onfocus='this.select();' value='+81 src/filemanager/ioblksize.h'  /> */</em>
<a id='L82' name='L82'></a>  82 <em class='brace'>{</em>
<a id='L83' name='L83'></a>  83     <a href='../Y/size_t.html' title='Multiple used in 726 places.'>size_t</a> <a href='../Y/blksize.html' title='Multiple used in 2 places.'>blksize</a> = <a href='../D/ST_BLKSIZE.html' title='Multiple defined in 2 places.'>ST_BLKSIZE</a> (<a href='../Y/sb.html' title='Multiple used in 19 places.'>sb</a>);
<a id='L84' name='L84'></a>  84 
<a id='L85' name='L85'></a>  85     <strong class='reserved'>return</strong> <a href='../D/MAX.html' title='Multiple defined in 2 places.'>MAX</a> (<a href='../S/src--filemanager--ioblksize.h.html#L76' title='Defined at 76 in src/filemanager/ioblksize.h.'>IO_BUFSIZE</a>, <a href='../Y/blksize.html' title='Multiple used in 2 places.'>blksize</a>);
<a id='L86' name='L86'></a>  86 <em class='brace'>}</em>
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